Can Different Types of Brake Fluid Be Mixed Together?

[Doreen]

Brake fluid should not be mixed. Different types and brands of brake fluid contain varying compositions, and mixing them can lead to a decline in performance indicators and chemical reactions, reducing the vehicle's braking effectiveness and impacting the fluid's temperature resistance, which can compromise driving safety. Brake fluid is a functional liquid used to stop wheel rotation, serving to transmit energy while also providing anti-corrosion, anti-rust, and lubrication benefits. Types of brake fluid: Castor oil-alcohol type, made from refined castor oil and low-carbon alcohol; synthetic type, formulated with ethers, alcohols, esters, and additives for lubrication, oxidation resistance, rust prevention, and anti-rubber swelling; mineral oil type, produced from refined light diesel fractions with thickeners added. Precautions for using automotive brake fluid: If gasoline, diesel, or engine oil accidentally mixes into a synthetic brake fluid system, the incompatibility between fluids can reduce braking effectiveness. For vehicles driven normally for 40,000 kilometers or with brake fluid used continuously for over two years, the fluid may degrade due to prolonged use, necessitating timely replacement. Vehicles equipped with brake fluid level warning devices should monitor whether the warning light flashes and if the sensor functions properly. When brake fluid is low, it should be replenished promptly, and stored fluid should be kept between the marked minimum and maximum capacity levels. If braking feels inconsistent during normal driving, the brake fluid should be replaced immediately, with the braking system cleaned using alcohol beforehand. If the vehicle pulls to one side during braking, conduct a comprehensive inspection of the braking system. If the wheel cylinder rubber cup is excessively swollen, it may indicate poor-quality brake fluid. In this case, replace it with higher-quality fluid and change the rubber cup as well. During seasonal changes, especially in winter, if braking performance declines, the brake fluid grade may not suit winter conditions. Replace it with a low-viscosity fluid suitable for cold temperatures. Avoid mixing different types or brands of brake fluid. For specialized braking systems, use only the specified brake fluid. Different formulations can degrade performance, and even compatible or substitutable brands may underperform, so avoid long-term mixed use. If water contaminates the brake fluid or impurities/sediment are detected, replace or thoroughly filter the fluid to prevent insufficient braking pressure and compromised performance. Regularly replace brake fluid: Brake fluid volume fluctuates with temperature, and the reservoir's vent hole can introduce moisture or impurities, lowering the fluid's boiling point. Prolonged braking heats the system, potentially causing vapor lock (compressed air), leading to reduced braking or failure. For safety, replace brake fluid periodically.